When 2 mole of C2H4 is completely burnt then 2648 kJ heat is liberated and - Hc of C is -394kJ and - Hf of C2H4 is -52KJCalculate - Hc for hydrogen-

Given: 2 C_2H_4_( g ) + 6 O_2_( g )⟶ 4 CO_2_( g ) + 4 H_2O_( l ) ΔH = 2648 kJ 12×[ 2 C_2H_4_( g ) + 6 O_2_( g )⟶ 4 CO_2_( g ) + 4 H_2O_( l ) ΔH = ...

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Chemistry

Enthalpy of Combustion

When 2 mole...

Question

When $2$ mole of $C_{2} H_{4}$ is completely burnt then $2648$ kJ heat is liberated and $Δ H c$ of $C i s - 394 k J$ and $Δ H f$ of $C_{2} H_{4} i s - 52 K J$
Calculate $Δ H c$ for hydrogen.

Open in App

Solution

Given:-
$2 {C_{2} H_{4}}_{(g)} + 6 {O_{2}}_{(g)} ⟶ 4 {C O_{2}}_{(g)} + 4 {H_{2} O}_{(l)} Δ H = - 2648 k J$
$\frac{1}{2} \times [2 {C_{2} H_{4}}_{(g)} + 6 {O_{2}}_{(g)} ⟶ 4 {C O_{2}}_{(g)} + 4 {H_{2} O}_{(l)} Δ H = - 2648 k J]$
${C_{2} H_{4}}_{(g)} + 3 {O_{2}}_{(g)} ⟶ 2 {C O_{2}}_{(g)} + 2 {H_{2} O}_{(l)} Δ H = - 1324 . . . . . (1)$
$C_{(s)} + {O_{2}}_{(g)} ⟶ {C O_{2}}_{(g)} Δ H = - 394 k J$
${C O_{2}}_{(g)} ⟶ C_{(s)} + {O_{2}}_{(g)} Δ H = 394 k J$
$2 \times [{C O_{2}}_{(g)} ⟶ C_{(s)} + {O_{2}}_{(g)} Δ H = 394 k J]$
$2 {C O_{2}}_{(g)} ⟶ 2 C_{(s)} + 2 {O_{2}}_{(g)} Δ H = 788 k J . . . . . (2)$
$2 C_{(s)} + 2 {H_{2}}_{(g)} ⟶ {C_{2} H_{4}}_{(g)} Δ H = - 52 k J . . . . . (3)$
Adding equation $(1), (2) & (3)$ , we have
$2 {H_{2}}_{(g)} + {O_{2}}_{(g)} ⟶ 2 {H_{2} O}_{(l)} Δ H = - 588 k J$
$\frac{1}{2} \times [2 {H_{2}}_{(g)} + {O_{2}}_{(g)} ⟶ 2 {H_{2} O}_{(l)} Δ H = - 588 k J]$
${H_{2}}_{(g)} + \frac{1}{2} {O_{2}}_{(g)} ⟶ {H_{2} O}_{(l)} Δ H = - 294 k J$
Hence the value of ${Δ H}_{c}$ for hudrogen is $- 294 k J$ .

Suggest Corrections

Similar questions

Q. When

2

mole of

C_{2} H_{6}

are completely burnt,

3129 k J

of heat is liberated. Calculate the heat of formation of

C_{2} H_{6}

Δ H_{f}

for

{C O}_{2}

and

H_{2} O

are

- 395 k J

and

- 286 k J

respectively.

A gas mixture $3.67 L$ in volume contains $C_{2} H_{4}$ and $C H_{4}$ is proportion of $2 : 1$ by moles and is at $25^{\circ} C$ and $1 a t m$ . If the $Δ H_{C}$ ( $C_{2} H_{4})$ and $Δ H_{C}$ $(C H_{4})$ are $- 1400$ and $- 900 k J / m o l$ find heat evolved on burning this mixture

When 2 mole of $C_{2} H_{6}$ are completely burnt, 3129 KJ of heat is liberated. Calculate the heat of formation of $C_{2} H_{6} . △ H_{f}$ for $C O_{2} & H_{2} O$ are -395 KJ and -286 KJ respectively.